1. Field of the Invention
This invention relates generally to a forced cooling casting apparatus, and more particularly to a casting apparatus which carries out casting using a forced cooling method by placing a plurality of casting molds in a loop line (track).
2. Description of the Related Art
When aluminum alloys are cast in accordance with the prior art methods, an extended period of time is necessary for solidification, and undesirable directionality occurs during solidification, based upon the shape or casting molds, so that low quality castings with defects such as blow holes are likely to be obtained. Various improvements have been made to the casting methods per se. In accordance with Japanese Public Patent Application No. 86966/1983, for example, tubular members are disposed in the cavity of the casting mold and are entrapped by a molten metal poured into the cavity. This is also shown in U.S. patent application Ser. No. 814,929, filed on Dec. 30, 1985. See also U.S. patent application Ser. No. 853,721 having the same filing date as the present application and entitled "FORCED COOLING CASTING APPARATUS," both of which are incorporated by reference. A cooling medium such as water is caused to flow through these tubular members to promote solidification of the molten metal. According to this method, since directional solidification is obtained in an outward direction due to the tubular member being at the center, blow holes or the like are less likely to occur in the castings and the quality can therefore be improved. At the same time, various other methods are known to promote solidification, such as methods using a chiller, a mold cooling method and so forth, and these methods are combined with one another in various forms to eliminate the defects peculiar to casting.
Promotion of solidification is necessary from the aspect of production efficiency, but there are inherent limits to the cooling speed and cooling methods from the aspect of quality of the resulting castings. Therefore, as a method of promoting solidification and accomplishing mass production of castings, attempts have been made to turn the casting operations into a flow process by, for example, disposing a plurality of casting molds on a rotary circular bed and sequentially carrying out casting steps such as cleaning a mold, arranging the mold, inserting a core, clamping the mold, pouring molten metal, and so forth.
However, such a flow process uses a plurality of casting machines, so that necessary equipmeht becomes complicated in construction and the cost of production of castings becomes higher. Therefore, an improvement in production efficiency is deemed necessary in order to rapidly supply the products.